winapi - CDialog - 来自无模式对话框的 EndDialog？

Question

MS documentation (和 others )“明确”指出:

... Because the normal OnOk and OnCancel member functions of a CDialog object would call EndDialog, make sure your modeless dialog box does not call those functions and instead overrides

由于 CDialog::OnOk 有效地调用了 CDialog::EndDialog，该方法如下所示:

void CDialog::EndDialog(int nResult)
{
    ASSERT(::IsWindow(m_hWnd));

    if (m_nFlags & (WF_MODALLOOP|WF_CONTINUEMODAL))
        EndModalLoop(nResult);

    ::EndDialog(m_hWnd, nResult);
}

我们还可以检查the docs for ::EndDialog再次“明确”声明:

Dialog boxes created by the DialogBox, DialogBoxParam, DialogBoxIndirect, and DialogBoxIndirectParam functions must be destroyed using the EndDialog function. An application calls EndDialog from within the dialog box procedure; the function must not be used for any other purpose.

然而，我有一个 CDialog 派生类，它具有默认行为 wrt。 OnOK并且似乎当我使用非模态/无模态时一切正常。

即:* 当我关闭(无模式)对话框时，它被关闭/从 View 中删除。* 应用程序没有显示任何内存泄漏。 (MFC 调试构建)

那又怎样？我是否需要自己阻止 EndDialog 并调用 DestroyWindow 或不需要？

---

注意:我知道文档和“网络”是怎么说的。只是我还没有找到为什么我需要做不同的事情，这个类应该可用于无模式和模态模式，所以不必做任何不同的事情可能会很方便。 p>

Answer 1

MSDN Docs对于 CDialog::OnOK 明确指出

If you implement the OK button in a modeless dialog box, you must override the OnOK method and call DestroyWindow inside it. Do not call the base-class method, because it calls EndDialog which makes the dialog box invisible but does not destroy it

因此您需要覆盖 CDialog::OnOK 并在内部调用 DestroyWindow() -- 这是来自 MSDN 的修改示例:

class CDlg : public CDialog
{
    ...
    BOOL m_bModal;
    ...
}

CDlg::CDlg(CWnd* pParent /*=NULL*/)
: CDialog(CDlg::IDD, pParent)
{
    ...
    m_bModal = FALSE;
    ...
}

INT_PTR CDlg::DoModal()
{   m_bModal = TRUE;
    const INT_PTR rval = CDialog::DoModal();
    m_bModal = FALSE;
    return rval;
}

void CDlg::OnOK() 
{ 
   if (!UpdateData(TRUE)) 
   {
      TRACE(_T("UpdateData failed during dialog termination\n"));
      // The UpdateData routine will set focus to correct item
      return;
   }
   if (m_bModal)
       EndDialog(IDOK);
   else
       DestroyWindow();
}

void CDlg::OnCancel()
{
   if (m_bModal)
       EndDialog(IDCANCEL);
   else
       DestroyWindow();
}